1. Field of the Invention
The present invention relates to a method of sending an e-mail from a mail source to the mail address to a destination, a mail system, a mail address managing apparatus, and a computer-readable recording medium storing a mail system program, which are used in the method.
2. Description of Related Art
Mail systems of the type described distribute on the Internet e-mails sent by mail sources to destinations designated by the respective mail addresses of the e-mails.
FIG. 24 of the accompanying drawings is a block diagram showing a conventional mail system. The conventional mail system 1′ comprises, as shown in FIG. 24, mail servers 11 (11a, 11b) and clients 10 (10a-1, 10a-2, 10b-1 through 10b-3), which are individually connected to a network 12.
The individual mail server 11 (11a, 11b) manages mail addresses of the individual users. Specifically, the mail server 11 (11a, 11b) manages the individual mail addresses by managing a plurality of mail boxes (not shown) corresponding to the mail addresses of the individual users so that the e-mails sent from the clients 10 are stored separately in these mail boxes.
A mail server is known which sends an e-mail, stored in the user's mail box, to a mailer (mailing program) set in the individual client in response to the user's request.
Conveniently in the following description, it is assumed that a particular mail address is assigned to the individual client 10. And in FIG. 24, the mail system 1′ comprises two mail servers 11a, 11b, and five clients 10 (10a-1, 10a-2, 10b-1 through 10b-3) The mail server 11a manages the mail addresses set in the clients 10a-1, 10a-2, while the mail server 11b manages the mail addresses set in the clients 10b-1 through 10b-3.
Mailers are set one in each client 10; at the individual client, the user creates, sends and receives an e-mail using the mailer.
In the following description, reference alphanumeric symbol 11a or 11b is used to designate a single particular one of the plural mail servers, and reference number 11 is used to designate an arbitrary mail server.
Likewise, reference alphanumeric symbol 10a-1, 10a-2, 10b-1 through 10b-3 is used to designate a single particular one of the plural clients, and reference number 10 is used to designate an arbitrary client.
In this conventional mail system 1′, when sending an e-mail from the client 10b-1 (mail source) to the client 10a-1 (destination), firstly the mail-source client 10b-1 creates the e-mail and sends the e-mail to the mail address of the destination (client 10a-1) designated by the e-mail, using the mailer.
The e-mail sent from the client 10b-1 is temporarily sent to the mail server 11b, and then the mail server 11b examines the mail address of the destination described in the e-mail and sends the e-mail to the mail server 11a managing the destination client 10a-1.
Then the mail server 11a examines the mail address of the e-mail and stores the e-mail in the mail box of the destination client 10a-1. And the destination receives at the client 10a-1 the e-mail stored in the mail box in the mail server so that it is possible to read the e-mail sent from the client 10b-1 at the client 10a-1.
In this conventional mail system 1′, if the mail source has input a wrong mail address for the destination in an e-mail, the e-mail is sent to a wrong destination or the mail servers 11a, 11b notifies the mail source that the e-mail could not been sent because the destination of the e-mail is unknown.
Further, when e-mails of the same content are sent to a plurality of destination concurrently, the mail source creates a group mail list in which mail addresses of these destinations are registered as a set and selects this group mail list as the destinations of the identical e-mails so that the identical e-mails can be sent to the plural mail addresses at once.
FIG. 25 is a flow diagram illustrating the procedure of the conventional mail system 1′ when an e-mail has been sent to the old mail address after the mail address was updated.
In FIG. 25, arrows each labeled with a parenthesized number mean the matters “a certain process is carried out” or “a certain process occurs”, and the numbers in brackets designate the sequence in which these matters occur. Also in the following description, an arrow labeled with a number in brackets indicates the same meaning.
In FIG. 25, although a single mail server 11a and a single server administrator 14a are arranged on the upper side and a single mail server 11b and a server administrator 14b are arranged on the lower side, it is assumed in the following description that the mail address being managed by the mail server 11a shown on the upper side has been changed to the mail address being managed by the mail server 11b shown on the lower side.
The server administrator 14a manages the mail server 11a, while the server administrator 14b manages the mail server 11b. 
In FIG. 25, if the mail address of a destination has been updated, the server administrator 14a deletes the mail address (old mail address) of the destination in the mail server 11a (arrow labeled with (1)), and the server administrator 14b registers the new mail address in the mail server 11b when it becomes aware of the new mail address of the destination (arrow labeled with (4)).
If an e-mail has been sent from the mail source to the old mail address after the old mail address of the destination was deleted in the mail server 11a and before a new mail address of the destination is registered in the mail server 11b (arrow labeled with (2)), the mail server 11a notifies the mail source that the e-mail could not sent because the destination of the e-mail is unknown (error process) (arrow labeled with (3)).
Therefore, in the conventional mail system 1′, if the mail address of the destination has been updated, the mail source has to previously confirm a new mail address of the destination to send the e-mall to the new mail address, and has to change the mail address in the address book of the mailer at every updating of a mail address, which would be laborious and time-consuming in maintenance.
Particularly if many mail addresses are registered in the address book of the mailer, the maintenance work would be laborious. For example, if a group mail list is registered in the address book, it is essential to manage all the mail addresses of destinations, which are registered in the group mail list, so as to be kept the latest mail addresses always.
Further, if an e-mail has been sent to a plurality of mail addresses and it has been received from the mail server 11 an error message that the e-mail could not been sent because no destination corresponding to the mail address exists, it is difficult to understand whether the e-mail could not sent to only part of the mail addresses or whether the e-mail could not sent to each and every one of the mail addresses.
Following three attempts are known as solutions to the foregoing problems.
As a first solution, Japanese Patent Laid-Open Publication No. HEI 11-74931 discloses a technology of registering the current mail address and the new mail address on a home page and checks on the home page whether or not the mail address of the destination has been updated.
However, in the technology of Japanese Patent Laid-Open Publication No. HEI 11-74931, it is necessary to check the mail address of the destination on the home page at every time when sending an e-mail. And if this technology is adopted in a mailing list, it is also necessary to always check all the mail addresses registered in the mailing list; when the mail address has been found wrong, the e-mail will now be sent to the intended destination until the mailing list is updated manually.
As a second solution, Japanese Patent Laid-Open Publication No. HEI 11-65960 discloses a technology of describing information, which can specify an individual, in place of a correct account (mail address) if the account (mail address) of the destination is unknown or uncertain and some other personal information is known, so that an e-mail can be sent to the intended destination.
However, in the technology of Japanese Patent Laid-Open Publication No. HEI 11-65960, the mail source has to grasp whether or not the destination employs the system and also has to previously obtain personal information specifying the destination, which would cause a danger that information specifying an individual might be drained as picked up by a malicious third party.
Further, if the sever name (portion after @ in a mail address) has been updated due to provider change, company name change, staff reassignment (transfer) etc., the e-mail cannot be sent to the intended destination until the mail source previously obtains the new mail address of the destination. In the mailing list, it is very difficult to update the individual mail addresses.
As a third solution, Japanese Patent Laid-Open Publication No. HEI 11-184787 discloses a technology that the user, who can use a home page, registers a destination ID in URL (uniform Resource Locator) of its own home page to notify the destination.
However, in the technology of Japanese Patent Laid-Open Publication No. HEI 11-184787, it is absolutely essential to correlate the home page and member-dedicated BBS (Bulletin Board System) with each other so that the whole procedure of this technology cannot be achieved with BBS. Namely, it is impossible to complete all the processes only with the e-mail, which would be inconvenient.
Some types of the mail server 11 restricts receivable data size (data capacity) for a single e-mail; if an e-mail whose size exceeds the data capacity has been sent, the e-mail cannot be sent or part of the e-mail would be lost.
As a consequence, if an e-mail of the size exceeding the data capacity has been sent, the mail source has to compress or divide the e-mail into a size smaller than the data size receivable by the mail server 11. At that time, the mail source has to check various restrictions on the system, such as the data capacity of the destination, which of division and compression should be used, and the combining or extracting (extending to the original data) method usable by the destination, which would be laborious and time-consuming.
Further, if the mail source user sends an e-mail to plural clients 10, it is essential that the address book of the mailer at each of all the clients 10 to be used should be updated to have the latest mail addresses. And if different mailers are set in the individual clients 10, it would be difficult to share the address book.